The present invention relates to a new and distinct variety of walnut tree Juglans regia which has been denominated varietally as ‘Sexton,’ and more particularly to such a walnut tree which has a harvest date approximately one week earlier than the walnut tree variety ‘Chandler’ (U.S. Plant Pat. No. 4,388) and which further produces a walnut that is jumbo in size with a smooth, tan colored shell, and light colored kernels which can be processed in shell or cracked.
It has long been recognized as desirable to provide walnut trees bearing large crops which are ripe for commercial harvesting and shipment midseason and exhibit low susceptibility to walnut blight. The tree of the present variety, ‘Sexton,’ produces a nut which is similar in some respects to common walnut tree varieties such as ‘Chandler,’ (U.S. Plant Pat. No. 4,388) and ‘Tulare’ (U.S. Plant Pat. No. 8,268). However the new variety is ready for harvest approximately one week before ‘Chandler,’ and two weeks after the common reference cultivar ‘Payne’ (not patented).
The new Juglans regia walnut tree of the present invention was created at Davis, Calif. in 1990 by a controlled cross of the cultivar ‘Chandler’ (U.S. Plant Pat. No. 4,388) and UC 85-8 (not patented). The pedigree is illustrated (FIG. 1). UC85-8 is a germplasm introduction which originated in the Xinjiang Province of China, and was provided by Xi, Sheng ke, Chinese Academy of Forestry, Beijing.
Seeds from the cross were planted and the resulting 31 trees were carefully observed along with other trees in the walnut breeding program. When they began to bear nuts, data were collected annually on leafing date, first peak and last female flower bloom, first, peak and last male bloom, blight severity and yield (Table 1). Nuts were sampled, cracked, and data was collected on shell appearance, shell thickness, shell integrity, shell strength, nut weight, kernel weight, percent kernel, ease of kernel removal, kernel color, and percent kernel shrivel (Table 2). A single tree was selected from among progeny of this controlled cross based on its superior attributes. This selection was originally designated ‘UC90-31-10,’ and is now designated the ‘Sexton’ cultivar after Joseph Sexton, a historical figure said be responsible for the soft shell walnut industry in Southern California. ‘Sexton’ was originally asexually reproduced by grafting in Davis, Calif., Parlier, Calif., and Chico, Calif. ‘Sexton’ is stable and reproduces true to type.